The present invention relates to the analysis of a liquid sample. The invention will be described and explained hereinafter by reference to the biomedical monoparametric analysis of a sample of whole blood, but it must be understood that the present invention cannot be limited in its scope to this field of activity.
In accordance with Patent Application EP-A-No. 0,180,528, a device for analyzing a liquid sample has been described, comprising a compartmented casing, having the shape of a disk and possessing:
a container for at least one dose of a reagent and/or a diluent;
a chamber for calibration of a calibrated quantity obtained from the sample;
a chamber for mixing at least the calibrated quantity and the dose of reagent;
and, if required, an optical measurement cell communicating with the mixing chamber.
And the casing is intended to interact with a centrifuging apparatus, for the purpose of causing the liquids to circulate within the said casing under the action of the force of the centrifuge.
According to this patent application, in addition to the analytical device as such, there is also provided, fixed to the casing, an introduction device with stopper, which is intended to receive a portion (for example a few drops) of the sample to be analyzed.
If the solution according to Patent Application EP-A-No. 0,180,528 is used to analyze, for example, a plasma sample, this entails manipulating the said sample in addition to the necessary prior centrifuging of the sample of whole blood. This may result, first, in the loss of all or some of the sample to be analyzed, and secondly in contamination of the said sample, falsifying or preventing the subsequent analysis.
Moreover, with the above introduction device, there is never any certainty that the quantity introduced is sufficient for analysis. Alternatively, it is necessary to work with a greatly excessive quantity of sample, and there is then the risk of saturating the analytical device, with no further possibility of obtaining a reliable measurement.
The present invention relates to an analytical device permitting direct sampling of a determined and reliable quantity of the liquid to be analyzed.
According to the invention, the device comprises an independent cartridge which can be irreversibly clipped onto the casing and which comprises an inlet for introducing the sample to be analyzed, a receptacle for collecting the sample introduced, a means for metering the collected sample, connected to the receptacle via a capillary duct, and an outlet for a metered quantity towards a casing inlet which communicates with the calibration chamber of the said casing.
By virtue of the invention it is possible to take the sample to be analyzed directly with the cartridge, the sample always being limited to the same initial quantity, by virtue of the receptacle which is stoppered at the side opposite the inlet by the capillary duct. Subsequently, the cartridge being permanently clipped to the casing, it is possible to meter the sample into the cartridge, in order to introduce an exact and reliable quantity into the interior of the analysis casing as such.
Liquid, for the purposes of the present invention, is understood to mean any fluid capable of flowing, whether it be a liquid, a suspension or any other substance whose viscosity is compatible with flowing within the analytical device.
The manner in which the invention can be implemented, and the advantage deriving therefrom, will be more clearly apparent from the example of embodiment which follows, given by way of non-limiting indication, with reference to the attached figures.